Multicolor powder center for supplying at least one powder spraying device with different types of coating powder as required

ABSTRACT

A multicolor powder center supplies at least one powder spraying device with different types of coating powder as required. The multicolor powder center has at least one powder container for receiving coating powder and at least one pump unit comprising at least one powder pump, in particular a dense flow pump or a diluted flow pump. The pressure side of the at least one powder pump is fluidically connected or can be fluidically connected to the powder inlet of a powder spraying device. The at least one powder container has at least one suction channel which is preferably formed in a suction pipe and which has a suction opening that opens into the interior of the powder container and an opposite discharge opening that opens into a connection, wherein the suction side of the at least one powder pump can be fluidically connected to the connection of the powder container.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is the national phase of PCT Application No.PCT/EP2019/051642 filed on Jan. 23, 2019, which in turn claims priorityto German Application No. 102018000514.4 filed on Jan. 23, 2018, both ofwhich are incorporated herein by reference in their entireties.

BACKGROUND

The present disclosure relates to a multicolor powder center forsupplying at least one powder spraying device with different types ofcoating powder as required.

The multicolor powder center according to the present disclosure isparticularly suited to supplying powder to powder spraying devices usedin the electrostatic spray coating of objects with powder, in whichfresh coating powder (also called “fresh powder” herein) and potentiallyrecovered coating powder (also called “recovery powder” herein) aresituated in powder containers and supplied to one or more sprayingmechanisms, or powder spraying devices respectively, by a pump unithaving at least one powder pump, for example in the form of a powderinjector or in the form of a dense phase powder pump. The sprayingmechanisms/powder spraying devices can for example be manual guns orautomatic guns.

The present disclosure is based on the problem of powder coating systemsand the associated powder supply devices needing to be thoroughlycleaned when a change in powder is made (changing from one type ofpowder to another type of powder), and particularly when changing colors(changing from powder of a first color to powder of another secondcolor), since even just a few powder particles of the previous type ofpowder can result in coating errors when coating with the new type ofpowder.

The present disclosure solves the task of achieving the feasibility ofeasily realizing a quick change in powder or, respectively, realizingmulticolor spray coating as efficiently as possible.

SUMMARY

Accordingly, in particular specified is a multicolor powder center forsupplying at least one powder spraying device with different types ofcoating powder as required, wherein the multicolor powder centercomprises a first powder container for accommodating a first type ofcoating powder and at least one second powder container foraccommodating a second type of coating powder. Furthermore provided isat least one powder delivery device in the form of a pump unit having atleast one powder pump, in particular a dense phase powder pump or thinstream powder pump. The pressure side of the powder pump is fluidlyconnected or connectable to the powder inlet of a powder spraying devicesuch as, for example, a manual gun or an automatic powder gun.

According to one aspect of the present disclosure, provided inparticular is for the at least one pump unit and/or the powdercontainers to be movable relative to each other such that the suctionside of the at least one powder pump is fluidly connected or connectableto either the interior of the first powder container or the interior ofthe at least one second powder container as needed.

According to embodiments of the present disclosure, the pump unit is forexample movable relative to the powder containers such that the suctionside of the at least one powder pump is fluidly connected or connectableto either the interior of the first powder container or the interior ofthe at least one second powder container as needed.

As a result, the disclosed multicolor powder center comprising at leastone pump unit movable relative to the powder containers enables aneasily realized and in particular effective powder change or multicolorspray coating operation respectively. All that is necessary thereto isfor the pump unit to be transferred from a first powder container to asecond powder container so that the suction side of the pump unit canthen be connected to the interior of the second powder container.

According to one aspect of the present disclosure, a first cleaningstation is further provided for accommodating when needed residualpowder accumulating during the cleaning of the at least one pump unitand/or a line system leading from the pump unit to at least one powderspraying device and/or at least one powder spraying device, particularlywhen changing from a first type of powder to a differing second type ofpowder.

Alternatively or additionally thereto, a second cleaning station can beprovided for cleaning the at least one pump unit and/or a line systemleading from the pump unit to at least one powder spraying device and/orat least one powder spraying device as required, particularly whenchanging from a first type of powder to a differing second type ofpowder.

This ad hoc cleaning particularly occurs when changing from a first typeof powder to a differing second type of powder. In this context, it isconceivable for the pump unit to be movable relative to the cleaningstation such that it can be cleaned in or at the cleaning station asneeded and in particular flushed with cleaning compressed air.Alternatively thereto, it is conceivable for the cleaning station to bemovable relative to the pump unit such that the pump unit can be cleanedin or at the cleaning station as needed and in particular flushed withcleaning compressed air.

According to embodiments of the disclosed multicolor powder center, thecleaning station and/or the pump unit itself is allocated a drive sothat the cleaning station can thus be moved relative to the pump unitsuch that the pump unit can be cleaned in or at the cleaning station asneeded and in particular flushed with cleaning compressed air.

Preferential implementations of the disclosed multicolor powder centerprovide for a carriage or slide assembly to be allocated to the at leastone pump unit, by means of which the pump unit can be movably guided ina horizontal plane and above the powder container as well as relative toit. Alternatively or additionally thereto, a vertical guide unit canalso be allocated to the pump unit for vertically moving the pump unitor parts thereof relative to the powder containers when needed.

According to embodiments of the disclosed multicolor powder center, itis provided for a drive, in particular a linear drive, to be allocatedto the first powder container and/or the at least one second powdercontainer for moving the corresponding powder container relative to thepump unit when required. Particularly conceivable in this context is forthe first powder container and the at least one second powder containerto each be able to be moved relative to the pump unit independently ofone another.

According to embodiments of the disclosed multicolor powder center, theat least one pump unit comprises at least two powder pumps which are inparticular operable independently of each other, these being arranged inthe pump unit such that in a state during which the pump unit is coupledto a powder container or a cleaning station, the at least two powderpumps are each connected on the suction side to the interior of thepowder container or cleaning station.

For example, it is conceivable for a first and at least one furthersecond pump unit, each comprising at least one powder pump, inparticular a dense phase or thin stream powder pump, to be provided,wherein the pump units are movable relative to the powder containersindependently of one another such that:

the suction side of the at least one powder pump of the first pump unitand the suction side of the at least one powder pump of the at least onesecond pump unit are fluidly connected or connectable as needed toeither the interior of the first powder container or the interior of theat least one second powder container; and/or

the suction side of the at least one powder pump of the first pump unitis fluidly connected or connectable to the interior of a first of the atleast two powder containers and the suction side of the at least onepowder pump of the second pump unit is fluidly connected or connectableto the interior of the other of the at least two powder containers asneeded.

In a further development of the latter embodiment of the disclosedmulticolor powder center, the first and the at least one further secondpump unit can be moved relative to each other and relative to the powdercontainers in at least one horizontal direction. Alternatively oradditionally thereto, it can be provided for the first and the at leastone further second powder container to be able to be moved relative toeach other and relative to the first and the at least one second pumpunit in at least one horizontal direction.

One conceivable implementation of the disclosed multicolor powder centerprovides for a plurality of powder containers arranged arrayed togetherin a matrix, wherein the at least one pump unit is movable in a firsthorizontal direction and in a second horizontal direction orthogonal tothe first horizontal direction relative to the powder containers suchthat the suction side of the at least one powder pump is fluidlyconnected or connectable as needed to the interior of one powdercontainer of the plurality of powder containers.

Alternatively thereto, a plurality of powder containers arranged arrayedtogether in a matrix can be provided, wherein the powder containers aremovable in a first horizontal direction and in a second horizontaldirection orthogonal to the first horizontal direction relative to theat least one pump unit such that the suction side of the at least onepowder pump is fluidly connected or connectable as needed to theinterior of one powder container of the plurality of powder containers.

Alternatively thereto, a plurality of powder containers arranged arrayedtogether in a matrix can be provided, wherein the powder containers aremovable in a first horizontal direction and the at least one pump unitis movable in a second horizontal direction orthogonal to the firsthorizontal direction such that the suction side of the at least onepowder pump is fluidly connected or connectable as needed to theinterior of one powder container of the plurality of powder containers.

According to a further aspect of the present disclosure, the pump unitcomprises a docking unit via which the suction side of the at least onepowder pump can be fluidly connected as needed to the interior of one ofthe powder containers. Conceivable in this context is for the dockingunit to be allocated a vertical guide unit, by means of which thedocking unit can be moved in the vertical direction as needed relativeto the at least one powder pump of the pump unit and the powdercontainers.

The present disclosure further relates to a multicolor powder center forsupplying at least one powder spraying device with different types ofcoating powder as required, wherein the multicolor powder centercomprises at least one powder container for accommodating coating powderand a pump unit having at least one powder pump, in particular a densephase or thin stream powder pump, the pressure side of which is fluidlyconnected or connectable to the powder inlet of a powder sprayingdevice. According to this aspect of the present disclosure, it isprovided for a docking unit to be allocated to the pump unit, via whichthe suction side of the at least one powder pump can be fluidlyconnected as needed to the interior of the powder container.

The docking unit is preferably vertically movable as needed relative tothe pump unit and relative to the powder container for fluidlyconnecting or disconnecting the suction side of the at least one powderpump to or respectively from the interior of the powder container.

For example, the powder container can have at least one intake duct,preferably formed in an inlet tube, which has an intake opening thatempties into the interior of the powder container, and an oppositelydisposed delivery opening which ends at a connection, wherein thesuction side of the at least one powder pump can be fluidly connected tothe powder container connection via the docking unit. Conceivable inthis context is for the connection to be arranged in an upper region andin particular in a top cover region of the powder container, and namelyin such a way that the connection is fluidly connectable to the suctionside of the at least one powder pump of the pump unit via the dockingunit.

According to embodiments, the docking unit has a first connectionassigned to the suction side of the at least one pump unit and at leastone second connection assigned to the powder container, wherein thefirst connection is fluidly connected to the second connection via aline section, and wherein the line section is flexibly realized in sucha manner that the second connection can be moved a predefined distancerelative to the first connection. The predefined distance in particularcorresponds at least substantially to a vertical distance between thesecond connection of the docking unit and a connection of the powdercontainer.

Pursuant to embodiments of the docking unit according to the presentdisclosure, the second connection of the docking unit is ofcomplementary design to a connection of the powder container to theextent of it being able to be connected to the powder containerconnection such that the at least one powder pump of the pump unit canbe fluidly connected to a corresponding intake opening of an intake ductallocated to the powder container. For example, the second connection ofthe docking unit and/or the connection of the powder container is/arepreferably designed as a self-closing hose coupling, in particular abayonet coupling.

It is conceivable for a cleaning station to also be provided forcleaning the at least one pump unit and/or a line system leading fromthe pump unit to at least one powder spraying device and/or at least onepowder spraying device when required, in particular when changing from afirst type of powder to a differing second type of powder. The dockingunit allocated to the pump unit is preferably configured to fluidlyconnect the suction side of the at least one powder pump to a cleaningconnection of the cleaning station as needed.

According to embodiments of the disclosed docking unit, the docking unitand/or the at least one powder container can preferably be verticallymoved relative to each other. Expedient in this context is for thedocking unit to be allocated a vertical guide unit for moving thedocking unit or parts thereof in the vertical direction when needed.

The present disclosure further relates to a multicolor powder center forsupplying at least one powder spraying device with different types ofcoating powder as required, wherein the multicolor powder centercomprises at least one powder container for accommodating coating powderand at least one pump unit having at least one powder pump, inparticular a dense phase or thin stream powder pump, the pressure sideof which is fluidly connected or connectable to the powder inlet of apowder spraying device. According to this aspect, it is in particularprovided for the at least one powder container to have at least oneintake duct, preferably formed in an inlet tube, which has an intakeopening that empties into the interior of the powder container, and anoppositely disposed delivery opening which ends at a connection, whereinthe suction side of the at least one powder pump can be fluidlyconnected to the powder container connection.

Conceivable in this context is for the connection to be arranged in anupper region and in particular in a top cover region of the powdercontainer, and namely in such a way that the connection is fluidlyconnectable to the suction side of the at least one powder pump of thepump unit.

The at least one intake duct is formed in a dip tube extending into theinterior of the at least one powder container or in a side wall of theat least one powder container.

According to embodiments of the disclosed multicolor powder center, theat least one powder container comprises a substantially rectangular orcylindrical powder chamber for coating powder and a fluidizing devicefor introducing fluidizing compressed air into the powder chamber. Atleast one inlet opening emptying into the interior of the powdercontainer can be provided in a side wall or in a top cover of the atleast one powder container for the supplying of coating powder as neededduring a powder coating operation of the multicolor powder center or forselectively introducing compressed cleaning air during a cleaningoperation of respectively the multicolor powder center or the at leastone powder container.

Of advantage is the further providing of at least one outlet leading outof the interior of the at least one powder container for the dischargingof the fluidizing compressed air introduced into the powder chamber ofthe at least one powder container for alternatively discharging cleaningair introduced into the powder chamber during a cleaning operationtogether with, where applicable, the residual powder carried along bythe cleaning compressed air.

The powder chamber of the at least one powder container preferably hasat least one fluidizing compressed air outlet with an outlet opening fordischarging the fluidizing compressed air introduced into said powderchamber. The fluidizing compressed air outlet can comprise a vent linewhich is connected or connectable to a riser pipe outside of the powdercontainer so as to prevent the discharge of powder from the powderchamber of the at least one powder container during a powder coatingoperation of the multicolor powder center. Conceivable in this contextis for the at least one fluidizing compressed air outlet to have a ventline which is connected or connectable on one side to the outlet openingof the fluidizing compressed air outlet and which empties on the otherside into a suction funnel of a suction unit preferably designed as anair flow amplifier.

At least one level sensor is preferably further provided for detectingat least one powder level inside the at least one powder container. Theat least one level sensor is in particular a non-contact level sensorseparately arranged from the interior of the powder container outside ofthe powder container.

The powder containers can be fixed and adjoining self-cleaningcontainers or individual movable or portable powder containers.Particularly conceivable in this context is for the powder containers tobe integrated into an automatic powder feeding system so thatcommensurate coating powder can be supplied automatically, oralternatively automatically upon need, to the powder containers. Thepowder feeding system can for example be realized as a paternostersystem.

Each powder container can be provided with the following functions:

level sensor for level monitoring and corresponding communication;

powder fluidizing/preconditioning upon a change in powder type so thatpowder is conveyed immediately after docking;

integration of a sieve;

integration of a vibration unit;

sensor system for detecting the correct positioning of the powdercontainer;

code plate, barcode, RFID card or the like for detecting and/oridentifying the powder container or its content respectively;

connection to a larger fresh powder container (e.g. BigBag station)external of the multicolor center for the automatic replenishing ofpowder; and/or

connection to a powder recirculation system.

Conceivable in this context is for the multicolor powder center to beallocated a recovery powder recirculation system for refeeding recoverypowder into the first powder container and/or the at least one secondpowder container as required. The recovery powder recirculation systemcan comprise at least one return line, particularly in the form of areturn hose, which is in particular fluidly connected or connectable onone side to a powder coating booth or coating workstation and the firstpowder container and/or the at least one second powder container forrefeeding recovery powder into the respective powder container whenneeded. The at least one return line is preferably movable on a carriageor slide assembly, in particular horizontally, relative to the firstpowder container and/or the at least one second powder container.

Furthermore, the at least one return line can be movable, in particularvertically, relative to the first powder container and/or at least onesecond powder container in order to form a fluidic connection with therespective powder container.

According to embodiments, the multicolor powder center is allocated apowder container venting system for venting the first powder containerand/or the at least one second powder container as needed. The powdercontainer venting system can comprise at least one vent line,particularly in the form of a venting hose, which is in particularfluidly connected when needed or permanently to the first powdercontainer and/or the at least one second powder container for ventingthe respective powder container. Here, too, it is advantageous for theat least one vent line to be movable on a carriage or slide assembly, inparticular horizontally, relative to the first powder container and/orthe at least one second powder container.

The size of the powder container is preferably 5 to 150 liters dependingon the type of container.

Further powder provisionings such as devices for conveying directly froma powder box or powder barrel are conceivable.

According to embodiments of the powder containers used in the disclosedmulticolor center, each are equipped with a vibrating sieve device forspray coating powder. The vibrating sieve device can comprise a sieveand a vibrator for vibrating the sieve. The vibrator is designed forexample as a compressed air vibrator or ultrasonic sieve.

In a further development, at least one device is in particular providedfor measuring the air pressure prevailing within the interior of the atleast one powder container.

Advantageous in this context is for:

the volume of fluidizing compressed air supplied to the at least onepowder container per unit of time to be able to be regulated, preferablyautomatically, as a function of the air pressure prevailing in theinterior of the at least one powder container; and/or

the volume of cleaning compressed air supplied to the at least onepowder container per unit of time to be able to be regulated, preferablyautomatically, as a function of the air pressure prevailing in theinterior of the at least one powder container; and/or

the volume of fluidizing compressed air discharged per unit of time fromthe at least one powder container to be able to be regulated, preferablyautomatically, as a function of the air pressure prevailing in theinterior of the at least one powder container; and/or

the volume of cleaning compressed air discharged per unit of time via atleast one residual powder outlet to be able to be regulated, preferablyautomatically, as a function of the air pressure prevailing in theinterior of the at least one powder container.

BRIEF DESCRIPTION OF THE DRAWINGS

The following will reference the accompanying drawings in describingexemplary embodiments of the solution according to the presentdisclosure.

The drawings show:

FIG. 1a a schematic and isometric view of a first exemplary embodimentof the multicolor powder center according to the present disclosure;

FIG. 1b a schematic and isometric view of a second exemplary embodimentof the multicolor powder center according to the present disclosure;

FIG. 2a a schematic and isometric detailed view of a pump unit as usedin the exemplary embodiment according to FIG. 1 a;

FIG. 2b a schematic and isometric detailed view of a pump unit as usedin the exemplary embodiment according to FIG. 1 b;

FIG. 3a a further schematic and isometric detailed view of a pump unitas used in the exemplary embodiment according to FIG. 1 a;

FIG. 3b a further schematic and isometric detailed view of a pump unitas used in the exemplary embodiment according to FIG. 1 b;

FIG. 4 a schematic and side view of the pump unit according to FIG. 2b ;

FIG. 5a-d further exemplary embodiments of the disclosed multicolorpowder center shown schematically;

FIG. 6 a schematic and isometric view of a third exemplary embodiment ofthe disclosed multicolor powder center (without powder containers); and

FIG. 7 a schematic and isometric detailed view of a pump unit as used inthe exemplary embodiment according to FIG. 6.

DETAILED DESCRIPTION

FIG. 1a and FIG. 1b each depict schematic and isometric views ofexemplary embodiments of the disclosed multicolor powder center 1.

Briefly summarized, each exemplary embodiment of this multicolor powdercenter 1 comprises a plurality of powder containers 2.1-2.8 (for exampleeight in FIG. 1a ), which are designed to accommodate different types ofcoating powders. According to the depicted embodiment, each of theplurality of powder containers 2.1-2.8 comprises a substantiallyrectangular powder chamber for accommodating the corresponding coatingpowder.

The structure of the exemplary embodiments of the disclosed multicolorpowder center 1 is specifically that of a frame 15 having multipleadjoining powder containers 2.1-2.8 and a moving carriage(carriage/slide assembly 6) above the powder containers 2.1-2.8 whichconsists of a plurality of powder pumps 4 (here: dense phase pumps)integrated into a pump unit 3.1-3.6 and a vertically moving docking unit8 with a corresponding docking plate 9.

The powder containers 2.1-2.8 are usually filled with different types ofpowder. The powder containers 2.1-2.8 are designed so as to be removablefrom the row of containers. Guides and the like ensure that the positionof the powder container is centered and indexed. All of the powdercontainers 2.1-2.8 are connected to a central suction device which ventsexcess pressure in the powder containers 2.1-2.8 caused by fluidizationof the powder. In addition to its capping function, the top cover 11 ofeach powder container 2.1-2.8 has integrated inlet tubes with dockinginterfaces situated at the upper end (connections 10).

The driven and precisely positionable carriage (carriage/slide assembly6) with the pump unit 3.1-3.6 and the docking unit 8 travels along aguide rail 16 and positions precisely above a powder container 2.1-2.8.A vertical movement of the entire docking plate 9 of the docking unit 8connects the inlet sides of the powder pumps 4 to the inlet tubes of thepowder containers 2.1-2.8; the latter preferably being a self-centeringstructure.

Although not shown in the drawings, multiple powder spray guns can thusbe simultaneously connected to one powder container 2.1-2.8. The powderpumps 4 then start to convey powder from the powder container 2.1-2.8toward the guns.

When changing the powder (color change), the mechanism undocks from the“old” powder container 2.1-2.8 and the carriage (carriage/slide assembly6) travels into a cleaning position in which the powder-conveyingcomponents (in the direction of the gun as well as the suction hose) arecleaned. Afterwards, the “new” powder container 2.1-2.8 is approached.

The constant powder conveyance quality is achieved by the advantages ofa dense phase pump in particular and its integration into the systemwith the shortest possible intake distances.

FIG. 1a shows one embodiment example having a total of eight powdercontainers 2.1-2.8. An implementation with fewer, up to only two powdercontainers is also conceivable. Thus, FIG. 1b for example shows anembodiment having a total of four powder containers 2.1-2.4.

Particularly when there are more than for example ten powder containers,a second and further row can be positioned parallel to the first row ofcontainers (see FIG. 5d ). The rows of containers are in this casesecured to the floor on a separate support and the frame 15 with thecarriage (carriage/slide assembly 6) becomes the portal; i.e. isequipped with another drive and travels in the X direction to thecorresponding row of containers.

The variant schematically shown in FIG. 5a is designed pursuant to thedesign of FIG. 1 in which a pump unit 3.1 (or gun respectively) makesuse of a single type of powder. One (single) slide assembly 6 istherefore needed.

The variant schematically shown in FIG. 5b allows groups to be formed: afirst group of pump units 3.1, or a first pump unit 3.1 respectively,makes use of one type of powder and a further group of pump units 3.2,or a further pump unit 3.2 respectively, makes use of a different or thesame type of powder at the same time. To that end, two slide assemblies6 are necessary in this example. The practical application behind thisis one multicolor powder center 1 supplying for example two spraybooths.

In the variant schematically shown in FIG. 5c , each individual pumpunit 3.1-3.6 (or gun respectively) can be assigned to an individual typeof powder. To that end, one slide assembly 6 is required for each pumpunit 3.1-3.6. In practical applications, manual spray guns are hencegenerally used to coat small quantities (e.g. individual metal furniturecomponents processed according to the FIFO principle and thus havingdifferent color requirements).

For a large number of powder containers 2.1-2.12, types of powderrespectively, the entire pump unit 3.1 as schematically shown in FIG. 5dcan additionally be moved to a further row of powder containers.

Although not depicted in the drawings, at least one cleaning compressedair inlet can be provided in a side wall of each powder container2.1-2.12, to which a compressed air source can be connected during acleaning operation of the powder container 2.1-2.12 for removingresidual powder from the corresponding powder chamber via a compressedair line in order to introduce cleaning compressed air into the powderchamber. Further conceivable is the providing of a residual powderoutlet on the already mentioned side wall or the floor of the respectivepowder container 2.1-2.12 which has an outlet opening through whichresidual powder can be forced out of the powder chamber with the aid ofthe cleaning compressed air introduced into the powder chamber duringthe cleaning operation of the powder container 2.1-2.12.

The respective powder containers 2.1-2.12 of the exemplary embodiment ofthe disclosed multicolor powder center 1 depicted in the drawingspreferably further comprise an inlet opening for the supply of freshpowder and/or recovery powder as needed. It is of course alsoconceivable in this context to provide a respective separate powderinlet for fresh powder and for recovery powder in each case.

The respective powder containers 2.1-2.12 of the exemplary embodiment ofthe disclosed multicolor powder center 1 are preferably each allocated afluidizing device for introducing fluidizing compressed air into thecorresponding powder chamber. The fluidizing compressed air can beintroduced into the corresponding powder chamber through an end wall,longitudinal side wall, bottom wall or cover wall. Particularlyexpedient is for the bottom wall of the respective powder chamber to bedesigned as a fluidizing bed. The fluidizing bed should have multipleopen pores or small passage openings, through which fluidizingcompressed air can flow upward into the corresponding powder chamberfrom a fluidizing compressed air chamber disposed below the bottom wallin order to propel the coating powder therein into a state of suspension(i.e. fluidize) during the powder coating operation of the multicolorpowder center 1 so that it can be easily extracted with the aid of apowder delivery device in the form of a pump unit 3.1-3.6. Thefluidizing compressed air is fed to the fluidizing compressed airchamber through a fluidizing compressed air inlet.

So that the pressure within the respective powder chamber does notexceed a predefined or definable maximum pressure during the operationof the fluidizing device, each powder chamber of the multicolor powdercenter 1 comprises at least one fluidizing compressed air outlet havingan outlet opening for discharging the fluidizing compressed airintroduced into the powder chamber and for effecting pressureequalization. The outlet opening of the at least one fluidizingcompressed air outlet of each powder chamber of the plurality of powdercontainers 2.1-2.12 should in particular be dimensioned such that amaximum overpressure of 0.5 bar relative to the atmospheric pressureprevails in the corresponding powder chamber during the operation of thefluidizing device.

A valve or the like can also be affixed to the outlet opening in orderto vent only the powder containers which are under fluidizationpressure.

A central vent line connecting the powder chambers, which leads to acentral suction unit, is preferably provided to discharge the fluidizingcompressed air introduced into the respective powder chambers of thepowder containers 2.1-2.12.

In the schematically depicted exemplary embodiment of FIG. 1a , eachpowder container 2.1-2.8 has a preferably non-contact level sensor 17 inorder to detect the maximum permissible powder level in the respectivepowder chamber. Thereby conceivable is for a further level sensor 17 tobe provided, which is arranged with respect to the powder container2.1-2.12 so as to detect a minimum powder level, and as soon as thepowder reaches or drops below said minimum powder level, a correspondingmessage is sent to a control device to supply fresh powder or recoverypowder to the corresponding powder chamber via an inlet opening,preferably automatically.

The level sensor 17 for detecting the powder level in the correspondingpowder chamber is preferably a non-contact level sensor 17 and isarranged separately therefrom outside of the powder chamber. Thisthereby prevents contamination of the level sensor 17. The level sensor17 generates a signal when the powder level reaches a certain height.Multiple such powder level sensors can also be arranged at differentheights, for example for detecting predetermined maximum levels and fordetecting a predetermined minimum level.

The signals of the at least one level sensor 17 are preferably used tocontrol an automatic powder feed of coating powder into the respectivepowder chambers through corresponding powder inlets in order to maintaina predetermined level or predetermined level range therein even duringthe period when the pump unit 3.1-3.6 is extracting coating powder fromthe corresponding powder chamber and pneumatically conveying it topowder spraying devices or a single powder spraying device (or intoother containers).

During such a powder spray coating operation, cleaning compressed air isnot conducted into the corresponding powder chambers, or only at reducedpressure.

Although not explicitly depicted in the drawings, it is furtherconceivable for a device to be provided for measuring or determining theair pressure prevailing in the respective powder chambers. This isimportant insofar as ensuring that no excess pressure can build upinside the corresponding powder containers 2.1-2.12 from the introducingof fluidizing compressed air during the powder coating operation of themulticolor powder center 1, since the powder containers 2.1-2.12 aregenerally not designed as high-pressure containers. It is insofarpreferential for the maximum allowable overpressure in the powderchamber to not exceed the value of 0.5 bar.

Particularly conceivable in the last-mentioned embodiment is for the airpressure measured in the respective powder chamber of the individualpowder containers 2.1-2.12 to be fed to a control unit continuously orat predetermined times or upon predetermined events respectively,wherein the volume of fluidizing compressed air supplied per unit oftime to the powder chamber and/or the volume of fluidizing compressedair discharged from the powder chamber per unit of time via the at leastone fluidizing compressed air outlet is preferably automatically set asa function of the air pressure prevailing within the powder chamber. Incontrast, during the cleaning operation of the multicolor powder center1, it is preferential for the volume of cleaning compressed air suppliedto the respective powder chamber per unit of time and/or the volume ofcleaning compressed air discharged per unit of time via the at least oneresidual powder outlet to be preferably automatically set as a functionof the air pressure prevailing within the powder chamber with the aid ofthe control unit.

The disclosed multicolor powder center 1, as shown pursuant to anexemplary embodiment in the accompanying drawings, comprises at leastone pump unit 3.1-3.6. In the embodiment depicted by way of example inthe drawings, the pump unit 3.1-3.6 comprises a plurality of dense phasepowder pumps preferably able to be individually controlled by means ofthe cited control unit and each having a powder inlet for drawing incoating powder as needed from one of the powder containers 2.1-2.12 aswell as a powder outlet. The respective powder outlets of the powderpumps 4 of the pump unit 3.1-3.6 are fluidly connected or connectable ineach case to a respective powder spraying device.

As schematically depicted, the pump unit 3.1-3.6 is allocated a carriageor slide assembly 6, via which the pump unit 3.1-3.6 can be movablyguided in a horizontal plane and above the respective powder containers2.1-2.12 relative to same. To that end, the carriage or slide assembly 6allocated to the pump unit 3.1-3.6 comprises a corresponding lineardrive able to be controlled and positioned relative to the respectivepowder container 2.1-2.12 of the multicolor powder center 1 by means ofthe cited control unit.

The pump unit 3.1-3.6 is further allocated a vertical guide unit forenabling the vertical moving of the pump unit 3.1-3.6 or parts thereofrelative to the powder containers 2.1-2.12 of the multicolor powdercenter 1 when needed.

According to the embodiment of the disclosed multicolor powder center 1depicted schematically in the drawings, the pump unit 3.1-3.6 comprisesa docking unit 8, via which the powder inlets (suction sides) of thepowder pumps 4 associated with the pump unit 3.1-3.6 can be fluidlyconnected to the interior of one of the powder containers 2.1-2.12 asneeded. To that end, a vertical guide unit is allocated to the dockingunit 8, by means of which the docking unit 8 can be moved in thevertical direction as required relative to the respective powder pumps 4of the pump unit 3.1-3.6 and the powder containers 2.1-2.12.

The docking unit 8 is vertically movable as needed relative to the pumpunit 3.1-3.6 as well as relative to the powder container 2.1-2.12 forfluidly connecting or fluidly disconnecting the suction side of the atleast one powder pump 4 to/from the interior of the powder container2.1-2.12.

As can be seen from the detailed depictions in FIGS. 2a to 4, the powdercontainers 2.1-2.8 each have at least one intake duct preferably formedin a inlet tube which has an intake opening emptying into the interiorof the powder container 2.1-2.8 and an oppositely disposed deliveryopening which ends at a connection 10, wherein the suction side of theat least one powder pump 4 can be fluidly connected to the connection 10of the powder container 2.1-2.12 via the docking unit 8. The connection10 is arranged in an upper region and in particular in a top coverregion 11 of the powder container 2.1-2.8, and namely in such a way thatthe connection 10 is fluidly connectable to the suction side of the atleast one powder pump 4 of the pump unit 3.1-3.6 via the docking unit 8.

As depicted, the docking unit 8 has a first connection 12 assigned tothe suction side of the at least one pump unit 3.1-3.6 and at least onesecond connection 13 assigned to the powder container 2.1-2.12, whereinthe first connection 12 is fluidly connected to the second connection 13via a line section 14, and wherein the line section 14 is flexiblyrealized in such a manner that the second connection 13 can be moved apredefined distance relative to the first connection 12. The predefineddistance corresponds to a vertical distance between the secondconnection 13 of the docking unit 8 and a connection 10 of the powdercontainer 2.1-2.12.

The second connection 13 of the docking unit 8 is of complementarydesign to a connection 10 of the powder container 2.1-2.12 to the extentof it being able to be connected to the connection 10 of the powdercontainer 2.1-2.12 such that the at least one powder pump 4 of the pumpunit 3.1-3.6 can be fluidly connected to a corresponding intake openingof an intake duct allocated to the powder container 2.1-2.12.

In particular, the second connection 13 of the docking unit 8 and/or theconnection 10 of the powder container 2.1-2.12 is/are designed as apreferably self-closing hose coupling, in particular a self-centeringand sealing coupling.

Although not shown in detail in the drawings, it is advantageous for acleaning station 5 to be further provided in order to be able to cleanthe pump unit 3.1-3.6 or the component parts of the pump unit 3.1-3.6respectively when needed, particularly when changing from a first typeof powder to a differing second type of powder.

To that end, it is expedient for the pump unit 3.1-3.6 to be movablerelative to the cleaning station 5 such that it can be cleaned in thecleaning station 5 when needed and in particular flushed with cleaningcompressed air.

Within the scope of this cleaning, it is further conceivable for thecleaning station 5 to not only be able to clean the pump unit 3.1-3.6and the component parts of the pump unit 3.1-3.6, in particular powderpumps 4, but also the line systems which lead from the pump unit3.1-3.6, or powder pumps 4 respectively, to the powder spraying devices.Further advantageous is for the cleaning station 5 to also be able to atleast partially clean the powder spraying device allocated to themulticolor powder center 1.

Particularly of advantage is for the docking unit 8 assigned to the pumpunit 3.1-3.6 to be designed to fluidly connect the suction side of theat least one powder pump 4 to a cleaning connection of the cleaningstation 5 when required.

FIG. 6 shows a schematic and isometric view of a further exemplaryembodiment of the disclosed multicolor powder center 1, although thepowder containers as well as the cleaning station are not depicted forthe sake of clarity.

FIG. 7 shows a schematic and isometric detailed view of a pump unit 3.1as used in the exemplary embodiment according to FIG. 6.

Briefly summarized, the disclosed solution is particularly characterizedby a very flexible changing of color and in particular during an ongoingcoating operation; i.e. in minimum time, whereby the powder feed qualityis at the same time ensured. A color change can in particular berealized within a maximum time period of 45 seconds, whereby themulticolor powder center 1 is able to provide a plurality of differentcolors or types of powder at the same time, for example a total of eightor more powder colors or powder types.

The powder pumps 4 of the pump units 3.1-3.6 ensure that the multicolorpowder center 1 can simultaneously supply a plurality of spray coatingdevices such as powder spray guns, for example. According to preferredimplementations of the multicolor powder center according to the presentdisclosure, up to 24 spray guns are connected to the correspondingpowder pumps of the multicolor center.

The individual powder containers are preferably equipped with afluidizing system, whereby the individual powder containers are ventedby way of a preferably centralized venting system.

The invention is not limited to the exemplary embodiments depicted inthe drawings but rather yields from an integrated overall considerationof all the features disclosed herein.

Thus, implementations of the disclosed multicolor powder center 1provide for a recovery powder recirculation system to be allocated tothe multicolor powder center 1 for refeeding recovery powder into atleast one of the powder containers 2.1-2.12 when required. The recoverypowder recirculation system can comprise at least one return line,particularly in the form of a return hose, which in particular is or canbe fluidly connected on one side when needed to a powder coating boothor a powder coating workstation and one of the powder containers2.1-2.12 for refeeding recovery powder into the respective powdercontainer 2.1-2.12.

The at least one return line of the recovery powder recirculation systemcan be arranged on a carriage or slide assembly so as to be movable, inparticular horizontally, relative to the first powder container2.1-2.12.

Alternatively or additionally thereto, the at least one return line canbe movable, in particular vertically, relative to the powder containers2.1-2.12 in order to form a fluidic connection with the respectivepowder container 2.1-2.12.

Also conceivable is for the multicolor powder center 1 to be allocated apowder container venting system for venting the powder containers2.1-2.12 as needed. The powder container venting system can comprise atleast one vent line, particularly in the form of a venting hose, whichis in particular fluidly connected as needed or permanently to thepowder containers 2.1-2.12 for venting the powder containers 2.1-2.12.The at least one vent line can thereby be movable on a carriage or slideassembly, in particular horizontally, relative to the powder containers2.1-2.12.

1. A multicolor powder center for supplying at least one powder sprayingdevice with different types of coating powder as required, wherein themulticolor powder center comprises: at least one powder container foraccommodating coating powder; and at least one pump unit having at leastone powder pump, including at least one of a dense phase powder pump orthin stream powder pump, a pressure side of which is fluidly connectedor connectable to a powder inlet of a powder spraying device, whereinthe at least one powder container comprises at least one intake ductformed in an inlet tube, which has an intake opening that empties intoan interior of the powder container and an oppositely disposed deliveryopening which ends at a connection, wherein a suction side of the atleast one powder pump is configured to be fluidly connected to theconnection of the powder container; wherein a powder chamber of the atleast one powder container has at least one fluidizing compressed airoutlet with an outlet opening for discharging fluidizing compressed airintroduced into said powder chamber; and wherein the at least onefluidizing compressed air outlet comprises a vent line which isconnected or connectable to a riser pipe outside of the powder containerto prevent discharge of powder from the powder chamber of the at leastone powder container during a powder coating operation of the multicolorpowder center.
 2. The multicolor powder center according to claim 1,wherein the connection is arranged in a top cover region of the powdercontainer in such a way that the connection is fluidly connectable tothe suction side of the at least one powder pump of the pump unit. 3.The multicolor powder center according to claim 1, wherein the at leastone intake duct is formed in a dip tube extending into the interior ofthe at least one powder container.
 4. The multicolor powder centeraccording to claim 1, wherein the at least one intake duct is formed ina side wall of the at least one powder container.
 5. The multicolorpowder center according to claim 1, wherein in order to increaseeffective flow area, the intake opening of the intake duct emptying intothe interior of the powder container has an elliptical shape.
 6. Themulticolor powder center according to claim 1, wherein the powderchamber of the at least one powder container comprises a substantiallyrectangular or cylindrical powder chamber for coating powder, and the atleast one powder container comprises a fluidizing device for introducingfluidizing compressed air into the powder chamber.
 7. The multicolorpowder center according to claim 1, wherein at least one inlet openingemptying into the interior of the powder container is provided in a sidewall or in a top cover of the at least one powder container forsupplying coating powder from a powder recirculation circuit or from afresh powder container external of the multicolor powder center, or formanually adding powder in a powder coating operation of the multicolorpowder center, or for selectively introducing compressed cleaning airduring a cleaning operation of the multicolor powder center or the atleast one powder container.
 8. The multicolor powder center according toclaim 1, wherein the at least one fluidizing compressed air outlet fordischarging fluidizing compressed air introduced into said powderchamber of the at least one powder container is further configured foralternatively discharging cleaning air introduced into the powderchamber during a cleaning operation together with any residual powdercarried along by the cleaning compressed air.
 9. The multicolor powdercenter according to claim 1, wherein the vent line of the at least onefluidizing compressed air outlet is connected or connectable on a firstside to the outlet opening of the fluidizing compressed air outlet, andempties on a second opposite side into a suction funnel of a suctionunit designed as an air flow amplifier. 10-11. (canceled)
 12. Themulticolor powder center according to claim 1, wherein at least onelevel sensor is further provided for detecting at least one powder levelinside the at least one powder container.
 13. The multicolor powdercenter according to claim 12, wherein the at least one level sensor is anon-contact level sensor which is separately arranged from the interiorof the powder container outside of the powder container.
 14. Themulticolor powder center according to claim 1, wherein at least onedevice for measuring the air pressure prevailing within the interior ofthe at least one powder container is further provided.
 15. Themulticolor powder center according to claim 14, wherein a volume offluidizing compressed air supplied to the at least one powder containerper unit of time can be regulated automatically, as a function of theair pressure prevailing in the interior of the at least one powdercontainer; and/or wherein a volume of cleaning compressed air suppliedto the at least one powder container can be regulated automatically, asa function of the air pressure prevailing in the interior of the atleast one powder container; and/or wherein a volume of fluidizingcompressed air discharged per unit of time from the at least one powdercontainer can be regulated automatically, as a function of the airpressure prevailing in the interior of the at least one powdercontainer; and/or wherein a volume of cleaning compressed air dischargedper unit of time via at least one residual powder outlet can beregulated automatically, as a function of the air pressure prevailing inthe interior of the at least one powder container.
 16. The multicolorpowder center according to claim 1, wherein the at least one powdercontainer comprises: a level sensor for level monitoring andcorresponding communication; and/or a powder fluidizing/preconditioningunit; and/or an integrated sieve; and/or an integrated vibration unit;and/or a sensor system for detecting correct positioning of the powdercontainer; and/or a connection to a further or larger fresh powdercontainer external of the multicolor powder center for the automaticreplenishing of powder.
 17. The multicolor powder center according toclaim 1, wherein the at least one powder container comprises a firstpowder container and at least one second powder container, and themulticolor powder center includes a recovery powder recirculation systemfor refeeding recovery powder into the first powder container and/or theat least one second powder container as required.
 18. The multicolorpowder center according to claim 17, wherein the recovery powderrecirculation system comprises at least one return line in the form of areturn hose, which is fluidly connected or connectable on one side to apowder coating booth and the first powder container and/or the at leastone second powder container for refeeding recovery powder into arespective powder container.
 19. The multicolor powder center accordingto claim 18, wherein the at least one return line is horizontallymovable on a carriage or slide assembly relative to the first powdercontainer and/or the at least one second powder container.
 20. Themulticolor powder center according to claim 18, wherein the at least onereturn line is vertically movable relative to the first powder containerand/or the at least one second powder container in order to form afluidic connection with the respective powder container.
 21. Themulticolor powder center according to claim 1, wherein the at least onepowder container comprises a first powder container and at least onesecond powder container, and the multicolor powder center includes apowder container venting system for venting the first powder containerand/or the at least one second powder container as needed.
 22. Themulticolor powder center according to claim 21, wherein the powdercontainer venting system comprises at least one venting hose that isselectively or permanently fluidly connected to the first powdercontainer and/or the at least one second powder container for venting arespective powder container.
 23. The multicolor powder center accordingto claim 22, wherein the at least one venting hose is horizontallymovable on a carriage or slide assembly relative to the first powdercontainer and/or the at least one second powder container.